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        검색결과 2,346

        61.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Due to the rapid growth of electrical vehicle and portable electronics markets, huge amount of the rare earth elements (REEs) and lithium have been required for the manufacturers globally. Moreover, after life time of the battery pass, the waste batteries containing valuable metal resources should be recycled due to competitions between the countries who manufacturing the batteries. Therefore, the REEs and lithium recoveries from the e-waste and wastewaters become issue recently. However, the commercialized technology for the valuable metal recovery is limited. In this study, the uses of the REEs and other valuable metal resources such as lithium, uranium, and gold and there recoverying methods according to the different water conditions were investigated and summarized. Moreover, the possible expectations and suggestions for the future application of the valuable resource recovery were conducted as a review.
        4,000원
        62.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzed Tuber melanosporum, Tuber aestivum,and Tuber magnatum, specifically the content of β-glucan, amino acids, nucleic acid-related substances, vitamin C, and ergosterol. The β-glucan content was highest in T. magnatum (20.54%). The free amino acid content was highest in T. aestivum, with the major amino acids being cystine, glutamic acid, and aspartic acid. The total amino acid content was the highest in T. magnatum, the primary amino acids being cystine, glutamic acid, and lysine. The content of nucleotide related compounds was the highest in T. magnatum (5.09 mg/100 g). The highest content of vitamin C (10.15 mg/100 g) and ergosterol (596.91 mg/100 g) was found in T. magnatum, which had the highest useful component content among the three truffles. Additional studies investigating the variation in useful components according to collection time and growth environment are needed.
        4,000원
        63.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        콘크리트 바닥판의 파손 등으로 인하여 강합성 거더 교량의 생애주기가 짧아짐에 따라 프리캐스트 바닥판을 사용한 모듈화 공법에 대한 연구가 활발히 진행되고 있으나, 바닥판의 해체 시 발생하는 분진 및 소음으로 인한 환경적 측면에 대한 연구는 미흡한 실정이다. 본 연구는 기존 용접 스터드 볼트를 대체할 수 있는 볼트 접합 전단연결재의 성능을 검증하기 위하여 정적강도 실험 및 피로강도 실험을 수행하였다. 실험결과 200만 회 피로하중에 대하여 실험체의 균열 및 파괴 양상은 관측되지 않았으며, 이후 실시한 잔류강도 실험 또한 정적강도 실험과 동일한 것으로 확인되었다.
        4,000원
        64.
        2022.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        For the selective catalytic reduction of NOx with ammonia (NH3-SCR), a V2O5WO3/TiO2 (VW/nTi) catalyst was prepared using V2O5 and WO3 on a nanodispersed TiO2 (nTi) support by simple impregnation process. The nTi support was dispersed for 0~3 hrs under controlled bead-milling in ethanol. The average particle size (D50) of nTi was reduced from 582 nm to 93 nm depending on the milling time. The NOx activity of these catalysts with maximum temperature shift was influenced by the dispersion of the TiO2. For the V0.5W2/nTi-0h catalyst, prepared with 582 nm nTi-0h before milling, the decomposition temperature with over 94 % NOx conversion had a narrow temperature window, within the range of 365-391 °C. Similarly, the V0.5W2/nTi-2h catalyst, prepared with 107 nm nTi-2h bead-milled for 2hrs, showed a broad temperature window in the range of 358~450 °C. However, the V0.5W2/Ti catalyst (D50 = 2.4 μm, aqueous, without milling) was observed at 325-385 °C. Our results could pave the way for the production of effective NOx decomposition catalysts with a higher temperature range. This approach is also better at facilitating the dispersion on the support material. NH3-TPD, H2-TPR, FT-IR, and XPS were used to investigate the role of nTi in the DeNOx catalyst.
        4,300원
        71.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The mineral content of Tricholoma matsutake was evaluated for comparison of mineral contents according to the area of cultivation. Ten domestic and thirty Chinese (10 Yanji, 10 Yunnan and 10 Tibet) T. matsutake specimens were assessed using an atomic absorption spectrophotometer (AAS) and inductively coupled plasma mass spectrometer (ICP-MS). The Na, Mg, K, and Ca contents of domestic T. matsutake were 128.12±85.25 mg/kg, 218.52±105.35 mg/kg, 7,534.58±2,691.52 mg/kg, and 17.69±7.14 mg/kg, respectively, while those of Yanji T. matsutake were 124.89±57.24 mg/kg, 64.07±27.52 mg/kg, 1,439.18±311.04 mg/kg, and 10.88±4.52 mg/kg, respectively. The Na, Mg, K, and Ca contents of Yunnan T. matsutake were 90.78±23.23 mg/kg, 77.40±28.36 mg/kg, 1,446.29 ±126.33 mg/kg, and 28.42±5.18 mg/kg respectively, while those of Tibet T. matsutake were 143.50±41.54 mg/kg, 124.64±50.18 mg/kg, 3,530.95±2,714.99 mg/kg, and 21.05±8.71 mg/kg, respectively. The Cu contents of domestic, Yanji, Yunnan, and Tibet T. matsutake were 105.43±32.97 mg/kg, 19.92±8.95 mg/kg, 54.51±16.91 mg/kg, and 64.80±23.01 mg/kg, respectively. Both domestic and Chinese T. matsutake samples showed significantly different K, Mg, and Cu levels in this study. Therefore, a comparative evaluation of the K, Mg, and Cu contents of multiple domestic and Chinese T. matsutake varieties is needed to determine the appropriate area of cultivation in the future.
        4,000원
        73.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fungi are organisms that must be monitored and controlled in order to preserve valuable paper records. They reduce the quality of paper records by degradation and/or discoloration. As an effort to understand fungal contamination in the National Archives of Korea, the concentration of fungi in the indoor air of the unsterilized record rooms has been reported. However, what species are present in the facilities is not much known. In the present study, we examined the fungi isolated from the National Archives of Korea and found among them that there are fungal species which are newly documented in Korea. They were identified based on morphological properties and nucleotide sequences analysis of the polymerase chain reaction-amplified the internal transcribed spacer region of rDNA, calmodulin gene, and beta-tubulin gene. We report Cladosporium parahalotolerans, Cladosporium subuliforme, Ochroconis mirabilis, Penicillium angulare, and Penicillium fundyense as new instances of fungal species in Korea. Among these five species, P. angulare is known to able to produce cellulase and O. mirabilis as an opportunistic pathogen of human and animals.
        4,000원
        74.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국제해사기구(IMO)의 대기오염물질 배출 규제에 대응하기 위해 액화천연가스(LNG)를 연료로 사용하는 선박이 증가하고 있다. 이와 함께 선박의 안정적인 연료 수급을 위한 LNG 벙커링 인프라 확대의 필요성이 대두되고 있다. LNG 벙커링은 TTS(Truck to ship), PTS(Pipe to ship), STS(Ship to ship) 3가지 방식으로 진행된다. 외국에서는 3가지 방식 모두 진행하고 있지만, 국내의 경우 인프라 부족으로 TTS 방식으로만 LNG 벙커링이 진행되고 있다. LNG 벙커링은 위험 요소가 많은 작업으로 안전한 벙커링 작업을 위해 작업 종사자의 역량 이 아주 중요하며 역량 강화를 위한 전문교육과정이 필요하다. 본 연구는 LNG 벙커링 전문인력 육성과 안전하고 체계적인 벙커링 작업 수행을 목적으로 LNG 벙커링 종사자 교육 콘텐츠를 설계하기 위해 진행되었다. 이를 위해 LNG 연료추진선박 및 벙커링 현황을 파악하고 국내외 관련 교육내용을 분석하였다. 더불어 전문가 설문을 통해 교육내용의 중요성에 대한 의견을 수렴하였다. 연구의 결과로서 다양한 교육 대상에 적합한 교육 콘텐츠 설계를 하고, 이를 총 4일이 소요되는 기초교육과 상급교육 과정으로 구분하여 제안하였다. 설계된 교육 콘텐츠를 바탕으로 우리나라 벙커링 환경을 충분히 반영하여 추가 연구가 진행된다면 LNG 벙커링 종사자 역량 증진을 도모하고 인적 자 원 육성에 큰 도움이 될 것으로 사료 된다.
        4,000원
        75.
        2022.08 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        PURPOSE: 본 연구의 목적은 둥근어깨자세(round shoulder posture)와 전방머리자세 (forward head posture)에 따라 폐활량 측정과 산소포화도 및 횡격막 움직임 크기의 상관관계를 알아보는 것이다. METHODS: 연구의 대상은 만성 심장질환 및 호흡기 질환을 가지고 있거나, 정신적, 인지적 장애가 있는 자, 척추옆굽음증(scoliosis)이 있는 자, 목과 갈비뼈 손상이나 수술 병력이 없는 50명의 자원한 사람으로 선정되었습니다. 통계분석은 피어슨(Pearson)의 상관분석을 실시한다. RESULTS:둥근어깨자세는 FVC,FEV1,FEV1/FVC%,PEF 에 대해 양의 상관계수를 보이고 이중 PEF가 가장 상관성이 높았다(p<.05). 횡격막 움직임의 크기(DMD)에 대해서도 양의 상관계수를 보였다. 그러나 TAD(table acromion distance)와는 음의 상관관계를, SPO2는 PM/C7~acro, TAD(table acromion distance) 둘다 음의 상관관계가 나타났다(P>.05). 전방머리자세는 CVA와 CRA 모두 FVC,FEV1,FEV1/FVC, PEF 비율에 대해 유의한 상관관계가 없다(p>.05). CRA와 DMD에는 유의한 차이가 있는 음의 상관관계가 나타났지만(p<.05), CVA와 DMD에는 유의한 상관관계가 발견되지 않았다. 또한 CVA와 CRA 모두 SPO2에 대해 유의한 상관관계가 없다(p>.05). CONLUSION: 결론적으로 전방머리자세의 각도와 둥근어깨 자세에 따라 폐활량과 횡격막 움직임에 영향을 미친다는 것을 확인 할 수 있었다. 하지만 좀더 많은 인원과 대상자들의 경직된 자세에 대해 제한할 방법을 추가적으로 찾을 필요가 있다.
        4,200원
        76.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Pacific giant octopus (Enteroctopus dofleini) is one of the most important species in the East Sea fishery of Korea. The annual production of Pacific giant octopus in 2021 was 3,880 metric ton between Gangwon province and Gyeongsangbuk province. Most of the fishing gears for the octopus fishery were based on behavioral properties such as thigmotaxis and chemotaxis. Wooden octopus box is also one of the fishing gears, which is application of thigmotaxis for the octopus capture in fishing industry. In this study, the tank experiments were designed to examine the behaviour and the effect of surface roughness to the infiltration of the octopus quantitatively. Three different types of octopus boxes were used for the experiments with different surface roughness on the average of 701.6 ㎛, 141.7 ㎛ and 2.09 ㎛ for each gear. 22 trials were conducted from June to September 2021. The normality of the experiments was tested using Shapiro-Wilk normality test (p-value < 0.05). The significance of results was conducted by Kruskal-Wallis rank sum test (Chi-squarded = 21, Degree of freedom = 3, p-value < 0.05). The use of wooden octopus box with rough surface was found to enhance the catch efficiency and observe infiltration behaviour of the octopus frequently.
        4,000원
        77.
        2022.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Single OLED and tandem OLED was manufactured to analyze the electroluminescence characteristics of DC driving, AC driving, and full-wave rectification driving. The threshold voltage of OLED was the highest in DC driving, and the lowest in full-wave rectification driving due to an improvement of current injection characteristics. The luminance at a driving voltage lower than 10.5 V (8,534 cd/m2) of single OLED and 20 V (7,377 cd/m2) of a tandem OLED showed that the full-wave rectification drive is higher than that of DC drive. The luminous efficiency of OLED is higher in full-wave rectification driving than in DC driving at low voltage, but decrease at high voltage. The full-wave rectification power source may obtain higher current density, higher luminance, and higher current efficiency than the AC power source. In addition, it was confirmed that the characteristics of AC driving and full-wave rectification driving can be predicted from DC driving characteristics by comparing the measured values and calculated values of AC driving and full-wave rectification driving emission characteristics. From the above results, it can be seen that OLED lighting with improved electroluminescence characteristics compared to DC driving is possible using full-wave rectification driving and tandem OLED.
        4,000원
        78.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 국립공원에서 자연의 소리는 생태계의 구성요소임과 동시에 탐방객들이 공원을 체험하는 중요한 요소이다. 따라서 국립공원 내 소음 분포 특성을 파악하고 자연의 음환경(Soundscape) 보존 및 복원을 위한 노력은 국립공원 관리 차원에서 중요한 과제 중 하나이다. 그러나 여전히 국내 국립공원에서는 소음 관리 및 음환경 보존에 대한 관심이 미약한 것이 사실이다. 무등산국립공원은 호남지역에서 가장 중요한 자연보호지역 중 하나로 계절별 동물이 우는 소리, 물소리, 바람 소리 등 탐방객들에게 자연의 소리를 제공할 수 있는 최적의 장소이지만 대도시에 인접해 있고 공원 내부로 도로 및 대규모 시설지가 인접해있는 등 소음이 발생하여 공원 내 음환경에 위협이 되고 있는 상황이다. 따라서 본 연구는 소음지도, 탐방로 소리등급도, 주요 지점의 음환경 녹음 데이터, 소리자원 분포도 등의 분석을 통해 무등산국립공원 내 소리 분포 특성을 파악하고 광범위한 소음의 영향을 나타냄으로써 음환경 관리의 필요성을 시사하고 있다는 중요성을 지니고 있다. 반면 본 연구에서는 연구 인력과 장비의 한계로 인하여 소음지도, 탐방로 소리등급도, 소리자원 분포도의 속성 데이터 수집 기간이 상이한 점이 한계점으로 남는다. 그러나 본 연구의 결과는 탐방 만족도 및 자연의 음환경 보존 등을 목표로 향후 지속적인 음환경 보존 및 관리를 위해 활용될 수 있는 기초자료가 될 것으로 판단된다.
        4,000원
        79.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate pesticide residues in 160 stalk and stem vegetables marketed in Northern Gyeonggi-do. The QuEChERS method using GC-MS/MS and LC-MS/MS was employed to analyze the residues of 341 pesticides in the samples. The maximum or lower than the residue limit was recorded in 75 samples (46.9%), while 4 samples (2.5%) exceeded the maximum residue limit (MRL). Thirty-nine kinds of residual pesticides were detected including fungicides (14), insecticides (22), herbicides (2), and plant growth regulator (1). Carbendazim and pendimethalin were the most frequelntly detected pesticides. Fenitrothion, procymidone, and diazinon exceeded MRL in garlic chives, and Welsh onion. This indicated that these vegetables along with water celery should be constantly monitored.
        4,000원
        80.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The smart factory is an important system that can reduce defects, maximize productivity, and respond to customer needs, from the labor-intensive era of traditional small and medium-sized manufacturing companies through the automation era to CPS using ICT. However, small and medium-sized manufacturers often fall short of the basic stage due to economic and environmental constraints, and there are many companies that do not even recognize the concept of a smart factory. In this situation, to expand the smart factory of small and medium-sized enterprises, the project to support the establishment of a smart factory for the win-win between large and small enterprises. The win-win smart factory construction support project provides a customized differentiation program support project according to the size and level of the company for all domestic manufacturing SMEs regardless of whether or not they are dealing with Samsung. In this study, we analyze the construction status and introduction performance of companies participating in the win-win smart factory support project to find out whether they have been helpful in management and to find efficient ways to improve support policies, and to suggest the direction of continuous support projects to improve the manufacturing competitiveness of SMEs in the future.
        4,000원
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